package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheCliten;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import org.apache.ibatis.session.ExecutorType;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.geo.Circle;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.SHOP_GEO_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Autowired
    private CacheCliten cacheCliten;

    @Override
    public Object queryShopById(Long id) {
        //缓存穿透
//        Shop shop = queryWithPassThrough(id);
//        cacheCliten.queryWithPassThrough(RedisConstants.CACHE_SHOP_KEY,id,Shop.class,this::getById,RedisConstants.CACHE_SHOP_TTL,TimeUnit.MINUTES);
        //互斥锁解决缓存击穿
//        Shop shop = queryWithMutax(id);

        //逻辑过期解决缓存击穿
//        Shop shop = queryWithLogicalExpire(id);
        Shop shop = cacheCliten.queryWithLogicalExpire(RedisConstants.CACHE_SHOP_KEY,id,Shop.class,this::getById,RedisConstants.CACHE_SHOP_TTL,TimeUnit.SECONDS);
        if (shop == null){
            return Result.fail("店铺不存在");
        }
        return Result.ok(shop);
    }

    public void saveShop2Redis(Long id,Long expireSeconds) throws InterruptedException {

//        Thread.sleep(200);

        Shop shop = getById(id);
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
        stringRedisTemplate.opsForValue().set(RedisConstants.CACHE_SHOP_KEY+id,JSONUtil.toJsonStr(redisData));
    }

//    private static final ExecutorService CACHE_BUILD_EXECYTOR = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors()+1);
//    public Shop queryWithLogicalExpire(Long id){
//        String key = RedisConstants.CACHE_SHOP_KEY + id;
//        //1，从redis中查询商铺缓存
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        //2，判断是否存在
//        if (StrUtil.isBlank(shopJson)) {
//            //3,不存在，直接返回
//            return null;
//        }
//        //4,存在则判断是否过期
//        RedisData bean = JSONUtil.toBean(shopJson, RedisData.class);
//        Shop shop = JSONUtil.toBean((JSONObject) bean.getData(), Shop.class);
//        LocalDateTime expireTime = bean.getExpireTime();
//        //5,未过期，则直接返回
//        if (expireTime.isAfter(LocalDateTime.now())){
//            return shop;
//        }
//        //6，已过期，缓存重建
//        String lockKey = RedisConstants.LOCK_SHOP_KEY + id;
//        boolean islock = tryLock(lockKey);
//        if (islock) { //获取锁成功，开启独立线程进行缓存重建
//            CACHE_BUILD_EXECYTOR.submit(()-> {
//                try {
//                    this.saveShop2Redis(id,20L);
//                } catch (Exception e) {
//                    throw new RuntimeException(e);
//                } finally {
//                    unLock(lockKey);
//                }
//            });
//        }
//        //返回过期的数据
//        return shop;
//    }

    //互斥锁解决缓存击穿
    /*public Shop queryWithMutax(Long id){
        String key = RedisConstants.CACHE_SHOP_KEY + id;
        //1，从redis中查询商铺缓存
        String shopJson = stringRedisTemplate.opsForValue().get(key);
        //2，判断是否存在
        if (StrUtil.isNotBlank(shopJson)) {
            //3,存在，直接返回
            Shop bean = JSONUtil.toBean(shopJson, Shop.class);
            return bean;
        }
        if (shopJson != null){
            return null;
        }

        *//**
         * 实现缓存重建
         * 1，获取互斥锁
         * 2，判断是否获取成功
         * 3，失败则休眠
         * *//*
        String lockKey = RedisConstants.LOCK_SHOP_KEY + id;
        Shop shop = null;
        try {
            boolean isLock = tryLock(lockKey);
            if (!isLock){
                Thread.sleep(50);
                return queryWithMutax(id);
            }
            //4，不存在，根据id查数据库
            shop = getById(id);
            //5,DB 不存咋,返回
            if (shop == null){
                //缓存控制，防止缓存穿透
                stringRedisTemplate.opsForValue().set(key,"",RedisConstants.CACHE_NULL_TTL,TimeUnit.MINUTES);
                return null;
            }
            //6，DB 存在，放入redsi，并返回
            stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } finally {
            unLock(lockKey);
        }

        return shop;
    }*/
    //缓存穿透解决
    public Shop queryWithPassThrough(Long id){
        String key = RedisConstants.CACHE_SHOP_KEY + id;
        //1，从redis中查询商铺缓存
        String shopJson = stringRedisTemplate.opsForValue().get(key);
        //2，判断是否存在
        if (StrUtil.isNotBlank(shopJson)) {
            //3,存在，直接返回
            Shop bean = JSONUtil.toBean(shopJson, Shop.class);
            return bean;
        }
        if (shopJson != null){
            return null;
        }
        //4，不存在，根据id查数据库
        Shop shop = getById(id);
        //5,DB 不存咋,返回
        if (shop == null){
            //缓存控制，防止缓存穿透
            stringRedisTemplate.opsForValue().set(key,"",RedisConstants.CACHE_NULL_TTL,TimeUnit.MINUTES);
            return null;
        }
        //6，DB 存在，放入redsi，并返回
        stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
        return shop;
    }

    @Override
    @Transactional
    public Result update(Shop shop) {
        Long id = shop.getId();
        if (id == null){
            return Result.fail("店铺id不存在");
        }
        updateById(shop);
        stringRedisTemplate.delete(RedisConstants.CACHE_SHOP_KEY + id);
        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //判断是否需要根据坐标查询
        if (x == null || y == null){
            // 根据类型分页查询
            Page<Shop> page = this.query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            // 返回数据
            return Result.ok(page);
        }
        //计算分页参数
        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;
        //查询redis，按照距离排序，分页 结果：shopId distance
        String key = SHOP_GEO_KEY+ typeId;
//        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo().search(
//                key,
//                GeoReference.fromCoordinate(x, y),
//                new Distance(5000),
//                RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end)
//        );
        GeoResults<RedisGeoCommands.GeoLocation<String>> results =  stringRedisTemplate.opsForGeo().radius(
                key,
                new Circle(x,y,5000),
                RedisGeoCommands.GeoRadiusCommandArgs.newGeoRadiusArgs().includeDistance().limit(end)
        );
        //解析出id
        if (results == null) {
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        if (list.size() <= from){
            return Result.ok(Collections.emptyList());
        }
        List<Long> ids = new ArrayList<>();
        Map<String,Distance> distanceMap = new HashMap<>();
        list.stream().skip(from).forEach(result->{
            Distance distance = result.getDistance();
            //获取店铺Id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            distanceMap.put(shopIdStr,distance);
        });
        //根据id查询shop
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = this.query().in("id", ids).last("ORDER BY FIELD( id," + idStr + ")").list();
        for (Shop shop : shops) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        // 根据类型分页查询
        // 返回数据
        return Result.ok(shops);
    }

}
